Protocol for Standard Empiric Antibiotic and Early Oral Transition in Children with Acute Osteomyelitis Based on Microbiologic Data from a Two-Year Retrospective Review

Background: Acute hematogenous osteomyelitis is seen primarily in children due to their rich blood supply of growing bones compounded by sluggish flow in the metaphyseal region that allows for bacterial proliferation. The dynamic state of growth in children mandates appropriate treatment to prevent chronic infection. Duration of 4 to 6 weeks of intravenous antibiotics has been considered standard of care; however newer studies suggest safe earlier transition to oral antibiotics. We aim to use the narrowest spectrum antibiotic as the empiric choice and hypothesize that oral transition will be as effective as a complete course of intravenous therapy.

Methods: A retrospective chart review was conducted of children identified through diagnostic coding seen at our pediatric infectious diseases clinic with osteomyelitis from June 2010 through June 2012.  Based on the microbiologic data we chose cefazolin as the empiric choice and developed a protocol for an early transition to oral antibiotic (cephalexin). We anticipate a prospective study over the next 2-3 years. Primary outcome measure will be recurrence in IV only group compared to oral switch group using χ² test. Secondary outcome of cost, hospital stay, line infection, and return to physical activity in these 2 groups will be measured by cross tab analysis.

Results: A total of 62 children had an osteomyelitis diagnosis and after exclusion of children with underlying medical conditions, 17 uncomplicated cases were selected. Methicillin sensitive Staphylococcus aureus (MSSA) was most commonly recovered  organism despite the high incidence of community acquired Methicilin resistant Staphylococcus aureus in our community of 33%. 10 (59%) were MSSA   cases and 2 (12%) were Streptococcus pyogenescases, 2 (12%) had no growth and  in 3(17%) cases no culture was done. IV only treatment was given in 11(65%) and oral switch was done in 6 (35%) cases. The recurrence risk was same (none) in both groups at 6-12 months follow up.

Conclusion: Our approach will target the most common organisms implicated in cases of acute uncomplicated osteomyelitis in the community. Early oral transition will prevent complications associated with prolonged IV therapy.